OKcupid.com
It's fantastic. All you need. The website is built on very geeky principles (by geeks) and uses a (to my knowledge) unique match-making algorithm based largely on user content and input. It also doesn't take itself too seriously - until very recently the "Visitors to my profile" page was titled "Stalkers".
They have a great Blog where they do large data mining studies (such as: which races get the most messages and from whom), and also provide helpful tips on editing your profile, choosing pictures, and what makes a good first contact message.
They also provide My Best Face, a free crowd-sourced service to determine which picture of you is the best - even giving you a breakdown showing which demographics particular photos resonate with.